Diseases caused by single gene defects such as Mucolipidosis Type IV (MLIV) present a significant challenge for effective therapy. MLIV, an autosomal recessive neurological disease, is due to defects in the mucolipin gene (MCOLN1) that results in functional loss of the encoded channel pore protein. Because replacement strategies such as gene therapy or recombinant protein delivery are not viable strategies, a promising alternative is to determine which other genes exhibit altered expression as a result of mucolipin deficiency in order to select druggable targets for therapeutic development. This proposal will identify which genes are involved in MLIV disease, as well as how their regulation is altered by key transcription factors in disease-associated pathways. The first phase involves identifying transcription factors that are differentially active in MLIV cells, followed by correlation with their differentially expressed genes. Two experimental approaches will be used: a cell-free protein-DNA binding method that quantitates transcription factor activity and chromatin immuno-precipitation in order to identify functional binding sites in living cells. In the next phase, analysis of these pathways will allow selection of target molecules, e.g., downstream encoded proteins, co-regulators of the transcription factors or upstream signaling molecules, for subsequent screening of drug candidates. Analysis of the gene regulation pathways compared to other diseases with similar phenotypes may also identify molecular changes in common that can be utilized in therapeutic strategies. Finally, results obtained by studying this disease can also be applied to other lysosomal disorders as well as other diseases due to single gene defects. [unreadable] [unreadable]